After direct reset, the fracture or crack is repaired by butt welding without disassembly and repair. This repair method is to correct the bending part of the main beam and directly make an uphill slope on the inner and outer surfaces of the broken or cracked part. The damaged parts are repaired by butt welding without disassembly, and some bandages can be strengthened at the damaged parts if necessary. Therefore, after the deformation of the manger behind the freight car is directly repaired, the broken or cracked part is repaired by butt welding, and it is not necessary to disassemble and repair the damage.